Small approved aquarium heater



FIG. 1 is an isometric view of a small approved aquarium heater showing my new design;

FIG. 2 is a side view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof; and,

FIG. 5 is a side view thereof taken 180 degrees from the view shown in FIG. 2. 

The ornamental design for a small approved aquarium heater, as shown and described. 